Railway signal system



Dec. 31, 1929. D. J. McCARTHY 1,741,642

RAILWAY SIGNAL SYSTEM Filed July 10. 1926 2 Sheets-Sheet 1 EJ L Dec. 31,1929. J, MCCARTHY: 1,741,642

RAILWAY SIGNAL SYSTEM Filed July 10,. 1926 2 Sheets-Sheet 2 iillillll,

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Patented Dec. 31, 1929 I UNITED STATES PATENT OFFICE DANIEL J. IGCABTHY,OI CARPENTERSVILLE, ILLINOIS ASSIGNOR TO CHICAGO BAIL- WAY SIGNAL ANDSUPPLY COMPANY, A CORPORATION OF ILLINOIS RAILWAY SIGNAL SYSTEMApplication flled July 10, 1928. Serial in. 121,530.

The invention relates to railway signals and especially of that class ofsignals that are localized along a railway track, for directing andwarning passing trains.

One of the objects of the invention is to provide reliable and eflicientmeans to shroud or conceal the signaling lenses and reflectors at alltimes except when it is desirable that a signal shall be transmitted,thereby to prevent the possibility of a phantom signal being projectedor propagated by reflection of light emanating from an extraneoussources.

A more specific object of the invention is to provide doors or shutters,which normally" obscure the color lens of a signal device when closed,and which are temporarily held open by an instrumentality, operable byelectric current, and located in the same circuit with the electric lampwhich supplies the light for the signal device.

A further object is to provide means to enclose the light reflectingparts within a signal casing automatically to prevent a.

phantom signal from being reflected therefromwhen the outer casing isopened for repairs.

Other objects, advantages, benefits and refinements will hereinafterappear from a consideration of the following description and theaccompanying drawings wherein:

On the drawings:

Figure 1 is a plan view of one form of a signal unit as it appears whentaken from its enclosing casing, and showing an electric motor foropening the opaque shutters which normally cover the color lens and whenthe lamp is energized.

Figure 2 is a side elevation of the device.

Figure 3 is a central plan section taken on line III-III' of Figure 2.

Figure 4 is an enlarged detail of shutter moving mechanism of the deviceas illustrated in Figure 5. t

Figure 5 shows an enclosing casing in plan section and the means ofautomatically closing the shutters before the lens when the door to thecasing is opened.

Figure 6 is a central vertical section of the same.

" Figure 7 is a schematic diagram of circuits.

In all the views the same reference char- A acters indicate similarparts. In optical instruments generall employed to project colored beamsof lig t, in railroad signal systems, the light therefrom is projectedby suitable reflectors or by lenses orlens combinations. The formertype, in which a suitable parabola or other reflector is used to projectthe'light, is preferable in so faras its capability to extend the beamsof light is concerned, but' it possesses the undesirable quality ofoperating to display phantom signals, that is to say, such an instrumentwill more readily exhibit a false signal that may originate from a beamof light directed into the Probably the most satisfactory lenscombination is shown in the drawings wherein 10 is the signal unit and11 is the containing casing. The frame 12 includes a larger metal ring13 and a smaller metal ring 14: arranged and held in coaxial relation byconnecting arms 15.

' The larger outer lens 16 is contained in the ring 13. It is preferablyclear glass. The lens 17 is the inner lens spaced from lens 16 and heldin ring 14. Lens 17 "is a color lens and give distinctive color for thesignal indications. The source of light for producing the li'cit signalis the well known incandescent lamp18. These lamps necessarily possess aglobular or cylindrical envelope. The walls of the envelope reflect toaconsiderable extent thru the lens combination light rays coming from anexterior source and which impinge thereon.

For producing the legitimate signal the light rays from the light source18 will pass thru lenses 17 and 16 and will thereby be refracted into a'beam of light of parallel rays. The light assing thru the colored lens17 will have con erred upon it the characteristic color of the coloredlens.

If the lens 17 be red the beam of hghtpassing thru it will be red. Iflight be PI'0180t8d into and thru this lens combination from the front,and from an extraneous source of llght, the rays of light therefrom willpass over the same course thru the lenses into the focal point of thelenses at which point lamp 18 1s located. Some of the light will bereflected from the outer surfaces of lens 16 and the outer surface oflens 17. This reflected light will produce no ill effect, as it iscolorless, but the light which passes inwardl thru lens 17 will be acolored light. These atter rays.

when they impinge upon the front surface of the glass envelope of thelamp 18 will be reflected back thereb and will again pass back thru thelenses an be projected as a colored beam thus producing a false orphantom signal when the lamp 18 is not energized.

It is to overcome the defects of signals heretofore in which the signaldevice is left open for entrance of light from an outside source that myinvention is intended.

In Figs. 1, 2 and in Fig. 7 an electric motor 20 is energized,coincidently with llghting the lamp 18, to open shutters 21-21 so thatthe intended signal may be displayed. The shutter 21 is secured to ashaft 22 to which is secured at one end an arm 23. Shutter 21' issecured to shaft 24 to which is also secured arm 25. The arms 23 and 25have their longer axes in planes angularly displaced about 45 degrees.The outer ends of arms 23 and 25 are connected together by a link 26.

In Fig. 1. the armature 27 of the motor 20 is oscillatable about theaxis 28 when the electromagnets 29-29 are energized to open the shuttersin a manner plainly obvious. A helical spring 30, wrapped about theshaft 24, automatically closes the shutters 21-21 when theelectromagnets 29-29 are deenergized and yieldingly holds the shuttersclosed to obscure the lens 17. The armature 27 carries a slotted arm 31providing two forks between which is included a pin 32 which projectsfrom the link 26. In Fig. 1 the shutters are closed and held closed bythe spring 30. When the magnets 29-29 are energized the armature 27 willbe rotated about 45 degrees in clock-wise direction, which will movearms 23 and 25 and link 26 and open the shutters as shown in Fig. 4.These shutters will remain open only so long as the motor is keptenergized. When the motor is deenergized by opening the electric circuitthe spring 30 will close the shutters. The shutters are painted black soas to be substantially non-reflecting in character.

In Fig. 1 a source of current 33, shown for convenience as a battery, isto energize the lam 18 and motor 20 when the switch 34 is closed. Whenthe signal lamp is lighted the red lens is thus uncovered. In ,Fig. 1the lamp 18 is shown in parallel circuit with the shutter closing motor.In Fig. 7 it is shown in series circuit with the motor.

The foregoing description concerns signal devices in which light from anextraneous source entering and (passing thru the lenses from the frontpro uces phantom signals. There is a probability that hantom signals maybe transmitted from t e signal device when the rear door of the casingis opened, by light from an extraneous source passing thru the lensesfrom the rear, and emanating from a point remote from the signal unit.To prevent this undesirable result arisin from such a contingency, Ihave arrange means for automatically closing the shutters to cover thecolored lens by the mere act of opening the casing door, and for openinthe shutter again by the act of closing said oor. This arrangement isshown more clearly in Figs. 5 and 6. A rear door 35 of the casing 11-containing the unit 10 is hin ed at 36 to the casing and is held inclose position by clip 37 or otherwise. A bracket 38 is secured to theunit 10 and has two outstanding arms 39 and 40. These arms areperforated for a reciprocable stem 41. The stem has a knob 42 on itsouter end. An arm 43 is secured to shaft 24 (see Fig 4). The arm isslotted to provide two parallel parts 44. A. pin 45 extends from thestem and enters the slot between the two parts 44-44 of the arm 43. Whenthe stem 41 is axially shifted it will open and close the shutters 21-21in an obvious manner. A spring 46 surrounds stem 41 and yieldingly holdsthe stem 41 in its outward position. When the stem is in this positionthe shutters are closed.

A spring clip device 47 is secured to the door 35. It has two springarms 48 with out-turned ends to engage the stem 41 and between which tocontain the knob 42. An abutment 49 pushes the stem or rod 41 inwardlyagainst the resistance of the spring a 46 when the door is being closed.This will move the arm 43 to position shown in Fig. 4, and open theshutters 21-21' rendering the lenses 16 and 17 visible from the front ofthe unit.

The spring arms 48-48 grasp the knob 42 and will pull the stem 41outwardly when the door 35 is being opened even though the spring 46 bebroken or refuses to function for other reason.

The description has more particularly referred to signal units of thedoublet lens type. When a parabola 50 is employed to project the light,the probability of a false signal being displayed by light proceedingfrom the rear when the door of the casing is opened, is less liable tooccur but phantom signal phe- 45 1s open and to expose the lens when thedoor nomenon from extraneous light passing thru the lenses from thefront is more likely to occur. In Fig. 2 I have shown the parabolaprojector merely-to indicate its relative position and not for thereason that it is desirable to use it in connection with a doublet lensunit.

Having described my invention, what I desire to secure by Letters Patentis 1. A railway signal unit having a colored lens; a pair of shutters; acasing enclosing the unit, and a door "for the casing and means operableby the said door to close and open the shutters to obscure the lens whenthe door is opened and to expose the lens two spaced rings; means tohold the rings in spaced relations; a colored lens in the rear ring; apair of shutters between the rings to obscure said colored lens whenclosed and means supported on the unit to close the shutters.

4. A railway signal unit having a casing; a door for the casing; a pairof axially spaced lenses in the casing, the inner lens of which iscolored; a substantially opaque shutter between the lenses, operabletoobscure the colored lens when closed and means operable by movement ofthe door to close the shutter when the door is opened. I

5. A railwa signal unit having a lens therein; movable shutter means toobscure and to expose said lens; a casing enclosing said unit, and adoor of the casing co-operating with said shutter-moving means to movethe shutter to obscure the lens when the door is closed.

6. A railway signal unit having a colored lens; a shutter movable toalternately obscure the lens and expose the lens; acasing enclosing theunit; a door for the casing, and connecting means, operable by movementof the door to close the shutter and obscure the lens when thedoor-"isopened, and to open the shutter and to expose the lens when the door isclosed.

In testimony whereof, I have hereunto subscribed my name.

DANIEL J. MoCARTHY.

